Copper alloy



.uy 65 i937o R. HENSEL ET AL 2,986,329

COPPER ALLOY Filed. May 26, 1956 Patented July 6. 1937 PATENT OFFICE' COPPER ALLOY Franz R. Hensel and Earl I. Larsen, Indianapolis, Ind., asslgnors to P. R. MalloryA & Co., Inc., Indianapolis, Ind., a corporation of Delaware Application May 2s, 1936, serial No. 81,820

claims. (ci. 'z5-,153)

This invention relates to alloys and more particularly to copper alloys of improved characteristics.

An object of the invention is to'produce ,an irn- 5 proved copper base alloy.

Another object is to produce a coppercadrnium alloy which can be age-hardened.

Other objects of the invention will be apparent from the following description taken in connection with the appended claims.

The present invention comprises the combination of elements, methods of manufacture, and the product thereof brought out Aand exemplified in the disclosure hereinafter set forth, Ithe scope of the invention being indicated in the appended claims. i

In the drawing: Figure 1 isa graph having curves illustrating the improvement in the hardness and electrical conductivity of the alloy of the present invention during age-hardening; y

Figure 2 is a graph showing the effect of temperature on the hardness of the finished alloy; and

Figure 3 is' a graph showing the elects of cold working the alloy. I

While a preferred embodiment of the invention is described herein, it is contemplated that considerable variation may be made in the method of procedure and the combination ot elements without departing'frorn the spirit of the invention.

Copper-cadmium alloys are frequently used at the present time for resistance welding electrodes,

spot welding electrodes, trolley wires, trolley wheels and electrical contactors of various types. These alloys, while having numerous advantages when used at low temperatures, are not entirely satisfactory when used even at moderately nigh 40 temperatures such as 300 to 350 C. According to the present invention these alloys are improved by the addition of zirconium. The improved alloys can not only be made of greater hardness than prior copper-cadmium alloys but are also capable of retaining their hardness at higher temperatures.

According to the preferred method of carrying out the present invention an alloy is made containing copper, cadmium and zirconium in substantially the following proportions:

Cadmium 0.1% to 2% Zirconium 0.1% to 5% Copper Balance It is possible likewise to improve the characteristics of other copper-cadmium alloys containing small percentages of additional ingredients by the addition of zirconium. Thus copper-cadmium/ alloys containing small proportions of silver, zinc, calcium, lithium, silicon or beryllium can be improved by the addition of zirconium in substantially the proportions indicated above.

The addition of. zirconium to the abovealloys renders them susceptible triage-hardening.

The alloy can be made according to standard 10 alloying methods. A preferred' method of alloying is to prepare a hardener alloy,containing 10-30% zirconium and then introduce a predetermined amount of this alloy `into a coppercadmium alloy of the desired composition. 15

After the alloy has been prepared according to standard alloying methods the heat treatment may be carried out as follows: The alloy in the form of a billet or any other form is raised in temperature to above 700 C. and preferablyto 20 a temperature in the order of 800 C. to 1000 C. The alloy is then quenched from this high tern-z perature and subsequently aged at a temperature below 700 C. and preferably in the range between 400 C. and 600 C. This heat treatment 25 results in a considerable improvement in hardness of the alloy. For example, 'an alloy having a Rockwell E hardness of 20 before the quenching and heat treatment may be given a Rockwell B hardness of or greater-byy the heat treating 30 process. Curve l0 in Figure 1 shows the increase in hardness during the age-hardening step of the heat treating process for an alloy of 1% cadmium, 1% zirconium and the balance copper.

Another remarkable effect of the heat treat- 35 ment ls a marked improvement in electrical conductivity. With some alloy combinations within the percentage range given above a conductivity of of that of pure copper has been obtained. Curve il in 'Figure l shows the improvement in 4g conductivity during age-hardening of the same alloy asthat whose hardness is represented in curve t0.

This alloy is, therefore, well suited for use at comparatively high temperatures since the hard- 45 ness and electrical conductivity are maintained for indefinite periods at the aging temperatures indicated. Cold worked and heat treated alloys of the present invention held for two hours at 450 C. retained a Rockwell B hardness of over 5d 70. In Figure 2, curve I2 illustrates the maintenance of hardness of a finished alloy at ele vated temperatures, the alloy being of the composition mentioned in connection with Figure l.

In addition to hardening by the heat treat- 55 ment described ,the above alloys are` alsoy susceptible to hardening by cold working. The

Rockwell B hardness, in one instance, can beA a tensile strength of 72,000 p. s. i. with 20%' elongation has been obtained ai'ter 30% cold reduction. Curve Hsin Figure 3 illustrates the improvement in hardness with cold working for the above alloy.

The alloys prepared as indicated above are well suited for the manufacture of-'castings such as commutator segments and Icollector rings for dynamo electric machines. In addition, as indicated above, these alloys are suitable for welding electrode tips and welding wheels. 'I'hey are also useful as current collecting nozzlescn automatic arc welding heads. y

I Another important use oi.' these high strength alloys is in the manufacture of cylinder heads, pistons and other parts of internal combustion engines, such as automobile engines, where high heat conductivity is needed.

while thepresent invention, as to its objects and advantages, has been described herein as carried out in specic embodiments thereof, it

30 is not desired to be limited thereby but it is intended to cover the invention broadly within the spirit and scope of the appended claims.r

What is claimed is:

l. An alloy containing about 0.1 to 2% cadmium, 0.1 to 5% zirconium and the remainder copper. v

2. An alloy containing about 0.1 to 2% cadmium, 0.1 to 5% zirconium and the remainder substantially all copper, characterized by a combination of high hardness and high electrical conductivity and further characterized bythe ability to maintain its hardness and high conduc-` tivity at temperatures in the order of 500 C.

3. An age hardened alloy containing about 0.1

to 2% cadmium, 0.1 to 5% zirconium and the remainder substantially all copper, characterized by a combination of high hardness and high electrical conductivity and further characterized by the ability to maintain its hardness and high conductivity at temperatures in the order oi' 4. A welding electrodescomposed o! about 0.1

'to 2% cadmium, 0.11to 5% zirconium and the 4remainder copper. 

